I started practicing piano quite seriously around 16 months ago, and whilst playing, I rather suddenly, after playing with force for a couple of hours straight, felt my left pinkie finger lock and become inhibited. I tried to put it back to a curved position, but could not as the PIP joint felt locked, after a few attempts I was able to curve my finger back down. Since then, my pinkie always locks in place and causes a small amount of pain when I fully extend it.
I was playing octaves, meaning my hand (which is certainly below average in size) was stretched out and extended as was my thumb and pinkie in order to reach the keys, and I was pressing forcefully on the keys.
Another, also related to piano, is a click or crunch I feel in my upper right wrist (right arm) when I play an arpeggio (or make a "sweeping" motion by moving one finger then the next in succession) with my ring and pinkie fingers. The clicking seems to be the tendons in my arm connected to those fingers rubbing together or overlapping, that's how it feels to me. They become movement inhibited whilst this happens, with no pain.
To add, I have caused week long bruising and swelling to most of my fingers (except the aforementioned left pinkie) by being goalie in soccer and various other activates, though they always, at least to my knowledge and senses, fully heal. No other related events.
I am a 19 year old male and athletic, arthritis does not run in my family.
Thank you very much for reading, apologies if this is difficult to answer, I admire this community greatly.